While VFDs are used in applications ranging from small appliances to
the largest of mine mill drives and compressors, about a third of the
world's electrical energy is supplied by electric motors in fixed-speed centrifugal pump, fan and compressor applications and VFDs' global market penetration for all applications is still relatively small. This highlights
especially significant energy efficiency improvement opportunities for
retrofitted and new VFD installations.

Over the last four decades, power electronics technology has reduced VFD cost and size and improved performance
through advances in semiconductor switching devices, drive topologies,
simulation and control techniques, and control hardware and software.

VFDs are available in a number of different low and medium voltage AC-AC and DC-AC topologies.